Oil well pumping system having reinforced plastic sucker rod

ABSTRACT

A system for pumping oil and a method for constructing a system in which a pump, disposed at the bottom of the well, is connected to the pump drive, at the top of the well, by a single length of reinforced plastic sucker rod having specific constructions and characteristics is disclosed.

United States Patent Wiechowski et al.

[ June 17, 1975 [54] OIL WELL PUMPING SYSTEM HAVING 3.034566 5/1962lflgckay 156/44! 1 S K D 3.129.282 4/1904 ynn 0 403/275 REINFORCED PLASTUC F R0 3.226.805 H1966 Scott et al 1 1 1. 403/275 [75] Inventors:Joseph W. Wnech skl. San 3.378.426 4/l968 Medney 1 1 150 441 Clemente;Delmar S. Miller, 3,442,738 5/l969 Scott et al 156/441 Newport Beach;Richard C, 3,474,737 Ill/I969 Norman ct alm. 417/53 Kostner, Orange a ofMarzocchi i. 3.684.622 8/1972 Goldsworlhy l56/44l [73] Assignee:Poly-Trusions, Inc., Santa Ana.

Cahf' Primary Examiner--William L. Freeh [22] Filed: Jan. 7, 1974Attorney, Agent, or FirmKnobbe, Martens. Olson. 1211 Appl. No.: 431,124Bear 52 us. (:1. 92/3; 417/545; 92 222 ABSTRACT [5|] Int. Cl. F041317/00; F04B 47/02 A System for pumping 0i] and a method for Construcb[58] Fleld of Search 4l7/545-554, ing a System in which a pump, disposedat the bottom 417/437! 572; 156/731 441; 403/275 404; of the well. isconnected to the pump drive, at the top 92/248 222 of the well, by asingle length of reinforced plastic sucker rod having specificconstructions and characl56] References and teristics is disclosed.

UNITED STATES PATENTS 3.002.046 9 1901 Clapper 403/275 12 Clams 8 Drawmgguns y g o o Y/ 00/55 Z, /1

PATENTEDJUN17 I975 SHEET PATENTEDJUN 17 ms v 8 9 9 l5 7 9 SHEET 3 V /V\\\\\\\\\\\\\\\\\\\\\\Y14 I OIL WELL PUMPING SYSTEM HAVING REINFORCEDPLASTIC SUCKER ROD This invention relates to petroleum engineering andproduction, and more specifically to systems and methods for pumpingpetroleum to the surface in oil wells.

More particularly, this invention relates to the construction of asystem for pumping oil in which a single, continuous sucker rod rangingfrom several hundred to several thousand feet in length is run down thewell and connected at the bottom to a pump and at the top to a drive forthe pump. A particular sucker rod comprising glass fibers extendinglongitudinally of the rod bonded together with a thermoset resin. whichmay have a passageway therethrough, may be filled to give a desireddensity. and may be protected with wrapped sheathing or extruded coatingto give greater strength and resistance to abrasion is disclosed.

Conventionally, sucker rods for oil well pumping systems have been madeof steel sections. These sections are carried to the oil well site andindividually extended down into the well and joined together usingspecial or conventional thread connections. Typically. each of theconnections is larger than the rod and, therefore constitutes anobstruction to the flow of oil out of the well. Steel rod weighs about 4pounds per foot and, consequently. a long sucker rod becomes so heavythat most of the energy input is required simply to move the rod up anddown. As a result, much energy is wasted and only a minor part of theenergy is available for actually pumping oil.

Other disadvantages of the conventional steel sucker rods include thetendency of connections to collect paraffin, which increases theobstruction to the flow of oil, thus reducing production and increasingpumping energy requirements. Also, the practical length of conventionalsteel sucker rods is limited by the high density inherent in suchconstructions. Depending upon the particular type of rod involved, thereexists a length beyond which it is not practical, for a giveninstallation, to extend the rod. When all of the pumping power availableis expended in simply raising and lowering the rod, or when the weightof the rod itself approaches the tensil strength of the rod at the upperend, no further extension of the rod is feasible.

In many oil fields. for example in the Midland-Odessa oil field area.corrosion of the steel sucker rods is an extremely serious problem,requiring that the sucker rods be replaced as often as every few weeks.

Cables, made of steel strands in the form of a wire rope, have beensuggested in lieu of sucker rods. This suggestion permits the use of acontinuous length without connections but does not solve the problem ofcorrosion and is not entirely satisfactory inasmuch as the cable isflexible and does not efficiently transmit the pumping energy from thepump drive to the pump. A sucker rod comprising a plurality of straight.longitudinally extended, spaced, flexible steel rod wires embedded inplastic, produced by extrusion of the plastic around the wires has beenproposed; however. to the extent that this proposal would tend toovercome the density and weight limitations inherent in the use of steelrods, it fails in loss of tensil strength. In addition, any small crack,pinhole, or other defect in the plastic surrounding the wires. wouldsubject the wires to corrosive action which would be even more severethan would be expected in the case of the conventional sucker rodbecause of the small amount of load bearing material. No successfulapplication of either of these proposed constructions is known.

The simple substitution of resin bonded glass fiber sucker rod sectionsfor the conventional steel rod has also been proposed. According to thisproposal, each length of the resin bonded glass structure is fitted ateach end with a connector, typically made of steel and having a muchlarger diameter than the rod, to permit the lengths of the rod to beconnected together in the manner typical of the conventional rodstructure. While this structure may reduce the weight of the sucker rodto some extent. much of the weight improvement is lost by the necessityfor numerous heavy, bulky steel connection fittings at the ends of eachsection of sucker rod. The obstruction of the oil flow channel typicalof the conventional sucker rod. is retained and perhaps even aggravatedby the necessity for the bulky connections. In addition, the connectionsare subject to corrosion.

All efforts to use resin bonded fiberglass connectors, by machining therod, using threaded connections. etc.. which are known, have notsucceeded. One of the principle problems appears to be that themachining of resin bonded fiberglass structure cuts the longitudinalfibers and weakens the rod and/or the connector. The use of numerousconnectors which weaken the rod or which are bulky and not easilyconnected and disconnected has proven unsatisfactory.

This invention overcomes many of the problems and disadvantages inherentin the prior art devices. Chemical resistance is provided, overcomingthe corrosion problem. Lightness coupled with high tensil strengthovercomes the weight problems of the prior art, and the oil flow channelis left free of obstruction. These and other improved features of thepresent invention will become apparent upon consideration of thefollowing.

A pumping system for oil wells and the like is constructed by placing apump in an oil well near the bottom in a reservoir of petroleum to bepumped to the surface. A pump drive is placed at the top of the oil welland the pump drive is connected to the pump by a sucker rod. In thisinvention, the sucker rod is of sufficient length to reach from thedrive to the pump and is constructed of a mulitplicity of glass fibersbonded together to form a semi-rigid rod. The bonding material is athermosetting organic resin. Fittings are fixed at respective ends ofthe sucker rod for connection to the pump and to the drive. The suckerrod is run into the well and connected at the lower end to the pump andat the upper end to the drive to complete the pumping system. The suckerrod is fabricated by pulling a plurality of rovings of glass fibers.each comprising a multiplicity of fibers, through a coating vat or otherresin application means to coat the fiber with a liquid thermosettingresin. The rovings coated with the resin are pulled through a formingdie and the formed rod is pulled through a curing station where thethermosetting resin is cured to form a single, semi-rigid continuous rodhaving a length sufficient to extend from the drive to the pump.

The rod may be made in many configurations. For example, the rod may behollow having a passage through the length thereof. The passage may befilled, fully or partially, with a weighting material. e.g. lead,particulate matter, beads, etc., and may include cables or conductors tocommunicate conditions in the well to the surface or to give controlsignals to devices in the well. The rod may be covered with one or morelayers of bonded glass fibers helically wound or woven around the rodand may be protected from abrasion by an extruded or otherwise appliedcovering of abrasion resistant material.

The system is illustrated schematically in FIG. 1 and FIGS. 2, 3, 4, 5and 6 illustrate various alternative configuration for the sucker rod.

FIG. '7 and FIG. 8 show examples of connector designs which can be usedto connect the rod to the pump or to the drive.

The method of constructing the oil pumping system of the invention isillustrated schematically in FIG. I in which the well is indicated at l.The sucker rod 2 is carried to the well site in one continuous piece, oris fabricated on site. In the exemplary embodiment illustrated, thesucker rod is reeled on very large diameter reels, indicated at 3, andrun down the well 1 and connected to the pump 4 which is disposed nearthe bottom of the well. Once the rod has been run down the proper lengthinto the well, the upper end is connected to a pump drive 5.

One embodiment of the sucker rod construction, absent the endconnectors, is illustrated in FIG. 2. The rod 10 is made up of amultiplicity of glass fibers running generally parallel to each otherlongitudinally of the rod. The glass fibers are indicated by numeral 12in FIG. 2 and are bonded together by a thermosetting resin 14.

The glass fibers may all be straight and unidirectional extendinglongitudinally of the rod. This gives great tensil strength to the rod,but such a rod is not highly resistant to longitudinal delamination;i.e. splitting along the longitudinal axis of the rod. Resistance tolongitudinal splitting can be improved substantially by using all spunglass fiber roving or a mixture of spun roving glass fibers and straightunidirectional glass fi bers, the latter giving a higher tensil strengththan the former. The spun glass fiber roving tends to give greatertransverse strength and resistance to longitudinal splitting at verymodest sacrifice in longitudinal tensil strength.

While this specification speaks mainly in terms of glass fibers, whichare a preferred fiber for the purposes of this invention because oftheir high tensil strength, the invention is not limited to glass fiberusage, but would include inorganic fibers of various types, e.g.graphite fibers, as well as natural and synthetic organic fibers such aspolyester fibers. Combinations of inorganic and organic fibers of thevarious types may be used to provide a proper balance of tensilstrength, weight, resistance to abrasion, chemical resistance andtransverse resistance to splitting. Glass fibers, other inorganic glassfibers and organic fibers, as well as various blends and mixtures of thesame may be used in the various structures comprising bonded fibersdisclosed hereinafter and discussed throughout this specification.

Polyester and epoxy organic resins are the preferred bonding materialsfor forming a rigid rod by bonding the fibers together. Polyesterbonding of glass fibers, as a fabrication technique, is well known.While less commonly used, epoxy is also well known as a bonding materialfor forming glass fiber reinforced articles. The techniques offormulation and application of these resins to produce various types ofstructures is well known in the art and abundant descriptive informationis available. Methods for forming elongate glass fiber reinforcedstructures generally of the type described herein are also well known.The pultrusion method, for example, is quite well known and varioustechniques for using this method in the fabrication of elongate articleshas been described, see, for example, US. Pat. Nosv 3,556,888 and3,674,601, and the method has been described in various technicalpublications; see, e.g. 1973-74 Modern Plastics Encyclopedia", page 428.Fibers, bonding resins, techniques and equipment generally suitable forproducing the sucker rod constructions described herein are described inl973-74 Modem Plastics Encyclopedia and in technical literature citedtherein, and generally in the literature.

Fibers such as carbon, graphite, boron, polyamides, polyesters, andother equivalents as well as glass may be bonded with polyesters,epoxies, thermoset acrylics, polycarbonates, vinyl esters, polyamides,ABS acrylonitrile-butadiene-styrene, and other equivalents as well asthe better polyester bonding resins.

The sucker rod 10 is described here as being semirigid. A semi-rigidrod, within the meaning of the present invention, is one which issufficiently flexible to be wound on a very large reel or equivalentcarrier or capable of being bent without permanent deformation in acurve having a large radius of curvature. Generally speaking, thesemi-rigid rod referred to in this invention has a diameter of fromabout inches to about 2 inches, or more, and its capability of beingbent is limited to a radius of curvature of at least about five feet andtypically of greater than 6.5 or 7 feet, but is must be capable ofbending on a radius of curvature of about 15 feet to 20 feet. Anothercharacteristic contemplated within the meaning of semi-rigid, as usedhere, is that the rod is sufficiently rigid to transmit compressionforce down the rod from the pump drive to the pump without being forcedagainst the walls of the casing in such a manner as to cause severeabrasion and frictional resistance to movement. This characteristic isto be distinguished from a wire cable or plastic coated wire cable,suggested previously, which did not 'permit compressive forces to betransmitted downwardly through the rod. The semi-rigid sucker rodc0ntemplated by this invention does not substantially reduce the pumpstroke at the bottom of the well by reason of slack in the rod, butrather transmits the majority of the downward movement of the pump driveto the pump.

In many instances no downward force is applied directly from the pumpdrive, the downward force being derived from the weight of the suckerrod in the well. The semi-rigid sucker rod of this invention transmitsthe weight of the rod to the pump, a characteristic which distinguishesit from the flexible cable like rods previously proposed which tend tosag, coil and fold rather than transmit the downward compressive forcevThe downward force resulting from the weight of the rod is an importantfactor in the design of sucker rods for oil well pumping. The steel rod,having a density of about 4 pounds per foot, is excessively heavy andtransmits an undesirable and unneccessary downward force to the pump andthe lower portions of the rod. A simple resin bonded glass fiber rodhaving a diameter of about l inch may be too light for some oil wellpumping systems. The density of such a rod will be in the range of about0.6 to about 0.8 of a pound per foot, depending upon the particularresin used and the ratio of resin to glass fiber in the rod.

Generally, a weight of at least about 1 pound per foot is desirable forproper operation of an oil well pumping system. One of the particularlyadvantageous features of this invention is that the density of thesucker rod can be varied uniformly along the length of the rod by addingfiller materials to the resin formulation. For example, in formulatingthe bonding resin, high density fillers, such as lead phosphate. orother heavy metal salts or high density powders are added to the bondingresin. When the bonding resin is applied to the glass fiber roving, thefiller is bonded as an integral part of the rod, increasing the densityof the rod. By selecting an appropriate ratio of resin to glass tofiller. a great variety of rod densities can be achieved.

Another method of achieving variable rod densites is illustrated in FIG.3 in which the rod is constructed in the manner previously described offibers 22 bonded together with a resin. filled or unfilled, 24, but therod has a central core 26 of lead or other high density material. Thecore may be non-load bearing, as in the case of lead, or it may be loadbearing material such as a steel wire. which would contribute to thetensil strength of the rod as well as increasing its density. The coremay extend the full length of the rod or only part of the length, wherevariable density is desired. The high density portion of the rod may beplaced at the bottom, at the top, or otherwise along the length of therod. This rod is formed in the same manner except that in fabricationthe glass fiber roving is positioned by the die around the central coreelement before the resin is cured.

A hollow center rod 30 made up of fibers 32 bonded together with a resin34, in the manner previously described, but constructed so as to providea hollow center 36 is illustrated in FIG. 4 as an alternative to theembodiment illustrated in FIG. 3. A pair of insulated wires, anelectrical cable, or other means of communicating sensing or controlsignals between the bottom of the well and the top may be included inthe hollow passageway through the center. Likewise, the density of therod may be varied by adding granular high density material, such as leadshot, after the rod is in position.

FIG. 5 illustrates a rod of the type illustrated in FIG. 3 withadditional structure; however, any of the preceeding rod constructionsand other rod constructions can be used in the embodiment used in H6. 5.The rod 40, of FIG. 5, is, in the particular rod illustrated, made up offibers 42 bonded by resin 44 surrounding a high density core 46 which,together, form the central rod construction 48. The rod 40 also includesa first sheath 50 and a second sheath 52 and an outer sheath 54. In theillustrative embodiment of FIG. 5, the sheath 50 is constructed offibers wound around the central rod structure 48 helically so as to havea substantial transverse directional component and bonded together toform an integral sheath enclosing the entire central rod structure.Organic or inorganic fibers may be used but for this application, theorganic polyamide (nylon), polyester Dacron), acrylic, polyvinylalcohol, polypropylene and other organic fibers being preferred.

Sheath 52 is similarly constructed but, in the exemplary embodiment ofFIG. 5, the sheath fibers are wound helically in the opposite direction.The purpose of the sheaths 50 and 52 is to protect the central loadbearing and load transmitting rod 48 from abrasion and corrosion and togive the overall rod 40 greater resistance to longitudinal splittingresulting from delamination or separation of the fibers in the centralrod structure 48. The density of the rod is increased by the addition ofthe sheath 50 and 52 and the tensil strength is also increased, but theincrease in tensil strength is secondary to the accomplishment of theprincipal purposes of sheathing the central structure and this in creasein tensil strength is not equivalent to that which would be accomplishedby merely increasing the diameter of the central structure.

The sheath 54 is an additional protective sheating extruded about theunderlying structure. Typically, this sheathing would be made ofpolyamide (nylon), ultra high density polyethylene, polypropylene,Teflon (polytetrofluoroethylene), or other synthetic extrudablematerial. This material preferably has a higher resistance to abrasionthan the underlying structure and may be self lubricating as is typicalof the polymers mentioned.

FIG. 6 illustrates another variation in which the rod 60 has a centralstructure made up of a multiplicity of fibers 62 bonded by resin 64 in ahollow configuration having a passage 66 extending longitudinally of therod. This passageway may be used in the manner previously discussed inconnection with the illustrative configura tion shown in FIG. 4. Thecentral core structure 68 is protected by a sheath 70 made up of amultiplicity of fibers, organic or inorganic as previously discussed,which are woven about the central structure to form a fabric sheathwhich is bonded together by a resin of the type previously discussed andwhich has a substantially transverse directional component. The centralstruc ture 68 is constructed in the manner previously discussed and thesheath is constructed by providing a weaving device at the point offabrication, either before or after setting the resin, to weave thefibers around the central structure. The sheath is then saturated with abonding resin and the sheath bonding resin is cured, as described in thepatent and literature references included herein by referencepreviously.

Sheaths of the type described with respect to the il- Iustrativeembodiment of FIG. 6 may be used in constructions such as illustrated inFIG. 5, alone or in combination with other sheaths. Likewise, the rod 60illustrated in FIG. 6 can be further protected by the addi tion of asheath of the type referred to at 54 in FIG. 5. Also, the centralstructure may be of any of the types heretofore described or referredto.

Any of the rod structures previously discussed can be given greatertransverse strength, resistance to splitting, by incorporating, in theresin, short fibers to improve the lateral strength of the constructionas well as by the use of spun glass fiber roving.

The advantages of the continuous reinforced plastic sucker rod in an oilwell pumping system include the following: The sucker rod is chemicallyinert and the resin bonding and the fiber system can be varied to meetvarious environments. Chemical inertness can also be varied to meetparticular requirements by appropriate sheathing materials. The rod isfree of joints and consequently the sucker rod is considerably lessexpensive to manufacture, to install in the well and to remove from thewell, and obviates the extreme disadvantage of the rod connectorsinterfering with flow through the casing and the collection of paraffinabout these connections. The weight and linear density can be regulatedto fall through the fluid column, ie, apply gravitational force of theproper magnitude to the pump, without slack, thus permitting efficientoperation of the pump. The weight of the rod and the downward force onthe pump can be varied to meet particular conditions of fluid viscosity,depth, etc. The longitudinal tensil strength, the transverse strengthand the circumferential integrity of the rod can be tailored to meetparticular strength requirements as required for handling and operation.The outer surface can be protected against abrasion as well asenvironment factors such as particularly severe corrosion. The rod canbe constructed with a passage through its center and, therefore, can beused for instrumentation and for venting of gasses or lighter fluidsfrom the bottom of the well or the injection of fluids down into thewell.

Any connector suitable for securing the ends of the rod to the pump andto the pump drive, respectively, may be used.

Unlike the segmented rods of the prior art, the single connector ateither end of this rod may be tapered to meet specific conditions andmay be protected from corrosion by appropriate coating, or otherprotective measures, since the position of the connector is fixed bybeing connected to the pump at one end and to the pump drive at theother. Joints as required to connect the sucker rod to the pump and tothe drive may be of the type described in National Bureau of StandardsRe port No. NBSIR 73-129 Evaluation of GRP Rod and Rope Materials andAssociated End Fittings", December 1972, Final Report.

The fittings illustrated in FIGS. 7 and 8 are intended as merelyillustrative of the types which may be used and selection of aparticular design depends on the environment and circumstances of use.In FIG. 7, the rod 80 extends into a cylindrical connector 82 which isthreaded at one end and tapered at the other. The rod is held in theconnector by a plurality of wedges illustrated at 84 and 86 which arepressed against the rod by the conical configuration of the cylinder 82.A potting compound, such as an epoxy thermosetting resin, indicated at88 bonds the end of the rod in the cylinder and bonds the wedges in thecylinder to the cylinder and to the rod.

In FIG. 8, the rod 90 is held in the cylinder 92 simply by a pottingcompound 94. The potting compound would typically be an epoxy or otherthermosetting adhesive resin. The thickness of the potting compound in94 is exaggerated in FIG. 8 for illustrative purposes.

In FIGS. 7 and 8, thread connectors are illustrated but it will beapparent that bayonet connectors, hook connectors, or connectors of anyother desired configuration may be utilized. These connectors may be ofsubstantial length to extend along the rod a sufficient distance todistribute the stress in the rod throughout the entire rod construction,thus obviating one of the difficulties faced in providing a multiplicityof connectors for fiberglass rods. Where many connectors are required,the connectors must, to be of useable weight and to minimizeconstruction time, be comparatively short and such connectors often tendto concentrate stresses in the skin portions of the rod.

It will be apparent that one or more of the protective sheaths may bepeeled back or removed at the entry point into the connector to providedirect fastening of the load bearing central structure to the connector.

In the illustrated embodiments, the rods are shown as being generallycircular; however, other cross sectional shapes, such as eliptical toaid in reducing the diameter of the core and giving the rod greaterflexibility in one dimension than in the other may be fabricated, asmight be required for particular systems.

The embodiments illustrated in the drawings are intended to illustratethe various constructions which may be used in the oil well pumpingsystem of the invention and are not intended to limit the invention tothe structures specifically illustrated. Likewise, while the preferredmaterials and embodiments have been principally discussed, and otherillustrative materials have been referred to, the itemization of variousspecific materials is not intended to be exhaustive of equivalentmaterials and equivalent steps. For example, while this inventiongenerally contemplates a single rod in a well, an equivalentconstruction can be found, in appropriate circumstances, where two orperhaps more long lengths of rod were so joined as, in effect, to be onelength or equivalent to one length within the system underconsideration. Finally, while the invention and many of its facets havebeen described in considerable detail, it is contemplated that the scopeof the invention will be according to the definitions in the claims andis not limited to the specific illustrative examples set forth in thebody of the specification.

What is claimed is: 1. A pumping system for oil wells and the like whichcomprises a pump in a well near the bottom thereof, a pump drive nearthe top of the well, and a sucker rod drive connecting the drive to thepump, the improvement wherein:

the sucker rod is of sufficient length to reach from the drive to thepump, said rod being constructed ofa multiplicity of glass fibers bondedtogether into a semi-rigid rod by a set organic resin; and

fittings affixed at the respective ends of the sucker rod for connectionto the pump and to the drive respectively.

2. The system defined in claim 1 wherein the sucker rod comprises asingle, continuous, semi-rigid rod consisting essentially of generallyparallel elongate glass fibers running lengthwise of the rod and resinbonding the fibers together.

3. The system defined in claim 2 wherein the sucker rod comprises asingle, continuous, semi-rigid rod consisting essentially of generallyparallel elongate glass fibers running longitudinally of the rod,thermoset resin bonding the fibers together, and a high density filler,said rod having a density of at least about I pound per foot and lessthan 4 pounds per foot sufficient to transmit energy from the drive tothe pump.

4. The system defined in claim 2 wherein the sucker rod comprises asingle, continuous, semi-rigid rod consisting essentially of generallyparallel glass fibers running lengthwise of the rod and thermoset resinbonding the fibers together in a rod configuration having a passagewayextending along the length of the rod.

5. The system defined in claim 4 wherein the sucker rod comprises adense filler material in said passageway for at least a portion of thelength of the rod of give the rod an average density of greater than Ipound per foot and less than about 4 pounds per foot sufficient totransmit pumping force efficiently to the pump.

6. The system defined in claim 4 wherein the sucker rod comprises meansin the passageway for permitting communication of sensing signals orcontrol signals be tween the pump and a station outside the well.

7. The system defined in claim 2 wherein the sucker rod furthercomprises at least one sheath enclosing the rod 8. The system defined inclaim 7 wherein the sheath comprises a multiplicity of glass fibershaving a substantial transverse directional component bonded together toenclose the rod to thereby increase the delamination resistance andabrasion resistance of the sucker rod.

9. The system defined in claim 8 wherein the sheath comprises amultiplicity of glass fibers running helically around the rod along thelength thereof, and thermoset resin bonding said helically extendingfibers together in at least one continuous sheath enclosing the rod.

10. The system defined in claim 8 including a sheath which is anextruded, flexible polymer layer having greater abrasion resistance thanthe resin bonded glass fiber material.

H. The system defined in claim 8 wherein the sheath comprises amultiplicity of glass fibers woven to form a fabric sheath around therod along the length thereof, and thermoset resin bonding said fibersheath together in at least one continuous sheath enclosing the rod.

12. The system defined in claim ll including a sheath which is anextruded, flexible polymer layer having greater abrasion resistance thanthe resin bonded glass fiber material.

i l =1 l

1. A pumping system for oil wells and the like which comprises a pump ina well near the bottom thereof, a pump drive near the top of the well,and a sucker rod drive connecting the drive to the pump, the improvementwherein: the sucker rod is of sufficient length to reach from the driveto the pump, said rod being constructed of a multiplicity of glassfibers bonded together into a semi-rigid rod by a set organic resin; andfittings affixed at the respective ends of the sucker rod for connectionto the pump and to the drive respectively.
 2. The system defined inclaim 1 wherein the sucker rod comprises a single, continuous,semi-rigid Rod consisting essentially of generally parallel elongateglass fibers running lengthwise of the rod and resin bonding the fiberstogether.
 3. The system defined in claim 2 wherein the sucker rodcomprises a single, continuous, semi-rigid rod consisting essentially ofgenerally parallel elongate glass fibers running longitudinally of therod, thermoset resin bonding the fibers together, and a high densityfiller, said rod having a density of at least about 1 pound per foot andless than 4 pounds per foot sufficient to transmit energy from the driveto the pump.
 4. The system defined in claim 2 wherein the sucker rodcomprises a single, continuous, semi-rigid rod consisting essentially ofgenerally parallel glass fibers running lengthwise of the rod andthermoset resin bonding the fibers together in a rod configurationhaving a passageway extending along the length of the rod.
 5. The systemdefined in claim 4 wherein the sucker rod comprises a dense fillermaterial in said passageway for at least a portion of the length of therod of give the rod an average density of greater than 1 pound per footand less than about 4 pounds per foot sufficient to transmit pumpingforce efficiently to the pump.
 6. The system defined in claim 4 whereinthe sucker rod comprises means in the passageway for permittingcommunication of sensing signals or control signals between the pump anda station outside the well.
 7. The system defined in claim 2 wherein thesucker rod further comprises at least one sheath enclosing the rod. 8.The system defined in claim 7 wherein the sheath comprises amultiplicity of glass fibers having a substantial transverse directionalcomponent bonded together to enclose the rod to thereby increase thedelamination resistance and abrasion resistance of the sucker rod. 9.The system defined in claim 8 wherein the sheath comprises amultiplicity of glass fibers running helically around the rod along thelength thereof, and thermoset resin bonding said helically extendingfibers together in at least one continuous sheath enclosing the rod. 10.The system defined in claim 8 including a sheath which is an extruded,flexible polymer layer having greater abrasion resistance than the resinbonded glass fiber material.
 11. The system defined in claim 8 whereinthe sheath comprises a multiplicity of glass fibers woven to form afabric sheath around the rod along the length thereof, and thermosetresin bonding said fiber sheath together in at least one continuoussheath enclosing the rod.
 12. The system defined in claim 11 including asheath which is an extruded, flexible polymer layer having greaterabrasion resistance than the resin bonded glass fiber material.